It is well known in the art that processes for thermal cracking of hydrocarbons such as ethane, propane, naphtha, and the like, produce a by-product referred to as pyrolysis gasoline or aromatic concentrate, which can be debutanized to form debutanized aromatic concentrate (DAC). This pyrolysis gasoline or DAC typically contains C.sub.5 and heavier hydrocarbons, such as C.sub.5 diolefins, C.sub.5 olefins, aromatics, cyclopentadiene (CPD), and dicyclopentadiene (DCPD).
It is desirable to convert the CPD to DCPD which is a valuable industrial chemical which can be used in the production of elastomers and unsaturated polyester resins.
Typical pyrolysis gasoline upgrading processes separate the pyrolysis gasoline into a C.sub.5 stream containing CPD and a C.sub.6 + stream. The C.sub.5 stream is then dimerized to form DCPD which is purified downstream. One problem with this process is that when the pyrolysis gasoline is obtained from storage, wherein a portion of the CPD is converted to DCPD, the separation of the pyrolysis gasoline into a C.sub.5 stream and a C.sub.6 + stream, and dimerization of CPD in the C.sub.5 stream to DCPD, will result in splitting the DCPD between the C.sub.5 stream and the C.sub.6 + stream, necessitating the added expense of recovering DCPD from both the C.sub.5 stream and the C.sub.6 + stream.
Therefore, development of a process capable of efficiently upgrading a pyrolysis gasoline, obtained either directly from a hydrocarbon thermal cracking unit or from storage, would be a significant contribution to the art.